U.S. patent application Ser. No. 684,307 filed Dec. 20, 1984 and entitled "High Speed Contact Driver for Circuit Interruption Devices" in the name of E. K. Howell describes the use of a bridging contact to make and break electrical connection between a pair of fixed contacts. A solid state switch electrically connected across the fixed contacts allows the contacts to separate with only a slight arc occurring between the fixed contacts and the bridging contact. The absence of the effects due to arcing allows the contacts to be made much smaller and hence more readily movable. This in turn beneficially allows circuit interruption during the early stages of the current waveform.
By diverting the current through the contacts immediately prior to separation, the contacts can be separated without sufficient current transfer to establish any arc. U.S. patent application Ser. No. 753,832 filed July 11, 1985 and entitled "Arcless Circuit Interrupter" also in the name of E. K. Howell describes one such solid state current interrupter and should be referred to for a good description of the circuits used to effect arcless interruption. When the contacts are separated with insufficient current transfer to establish an arc, the contacts can be made to interrupt the low current value with a minimum separation distance.
The purpose of this invention is to describe a high speed contact driver sufficient to rapidly separate a bridging contact from a pair of fixed contacts by means of the expansion properties of a piezoelectric material when excited by a DC voltage pulse.